Rear defrost, and heated seats

Discussion in 'General Motoring' started by Ritchard Findlay, Oct 14, 2003.

  1. Hello Volvo friends,

    Forgive me for asking what are likely common questions, but I have searched
    the various resources, and cannot find adequate answers.

    I have an '89 740 GLE (nice) that I have had for a few weeks. As winter
    comes rolling down the road, I have to fix a couple of things. As late as I
    believe two weeks ago, my rear defrost worked. Now it doesn't. Yesterday
    my Father-in Law and I got the multi meter out, found that we have
    continuity through the system downstream of the switch, so the elements must
    be okay. We pulled the switch out and fiddled with the relay, and I thought
    made it work. Of course on a sunny Thanksgiving (Canada) Monday afternoon,
    I couldn't test it, so waited for some fog this morning. I was disappointed
    to find that it didn't work. Anybody got any ideas? Is there a
    comprehensive troubleshooting sequence posted someplace?

    I am also skeptical of the heated seats. I turn the switches on, nothing
    happens. Then in further reading yesterday, I find that they are
    thermostatically controlled - leather seats. My last two Volvos were
    plainer. How should I expect them to work? Does thermostically controlled
    mean that they will not turn on on a warm day, or that they will turn off
    when they hit a certain temp? I pulled one seat apart, and forced the
    heater to work by flipping the switch inside the relay. So the element, at
    least on the passenger side is okay. I also took one bit of advice from
    Swedishbricks and resoldered the guts of that relay. Still no heat without
    forcing it. What gives? If it is a relay that is required, where do you
    get them? I couldn't find one anyplace online, and am shy about paying
    dealer prices for stuff like that.

    Any help?


    Ritchard Findlay, Oct 14, 2003
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  2. Ritchard Findlay

    Mike F Guest

    Your father has started the test procedure correctly. You just need to
    do the testing when you can check that the defroster is working.
    The seat heat time is determined by relay temperature. Toss the relays
    into the freezer for an hour or so, and repeat the test. (Seat heaters
    should be working at our recent morning temperatures. Mine are.)
    Mike F, Oct 15, 2003
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